Dispersants for a hydraulic composition are chemical admixtures, and used for dispersing cement particles, thereby reducing a unit water quantity necessary for achieving a required slump and enhancing workability and the like of a hydraulic composition. There are conventionally known dispersants, including naphthalene-based dispersants such as a naphthalenesulfonic acid-formaldehyde condensate, polycarboxylic acid-based dispersants such as a copolymer of a carboxylic acid and a monomer having an alkylene glycol chain, and melamine-based dispersants such as melaminesulfonic acid-formaldehyde condensate.
Dispersants are also used in combination with an alkanolamine for a hardening strength at an early stage of a concrete. For example, JP-A2007-31166 discloses a splay material having a low alkali content and exhibiting good early strength development, that is provided by adding an acidic liquid hardening-accelerator containing aluminum, sulfur, and an alkanolamine, powder aluminium sulfate, and one or more inorganic compounds selected from the group having sulfates, aluminates, and hydroxides to a cement concrete. This document also discloses that a known water-reducing agent (dispersant), such as a lignosulfate-based one, a naphthalenesulfonic acid-based one, or a polycarboxylic acid-based one, can be used to improve fluidity of a cement concrete.
JP-A 2000-511151 discloses a hardening-accelerator of an alkali metal salt or an alkaline earth metal salt of an organic or inorganic acid, and a multifunctional admixture containing a fatty acid aminosulfonic acid surfactant for a purpose of provide a multifunctional hydraulic cement admixture having both hardening-accelerating and air entraining of a hydraulic composition. This document also discloses a composition admixture further containing a water-reducing agent containing an alkali or alkaline earth metal salt of lignosulfonic acid, polycarboxylic acid, a naphthalene-sulfonic acid condensate, a melamine-sulfonic acid condensate, a hydroxylated carboxylic acid, or a hydrocarbon, and a composition admixture further containing an early strength enhancer containing an alkanolamine. This document describes that a preferred admixture contains triethanolamine or triisopropanolamine as the alkanolamine and calcium lignosulfonate as the water-reducing agent.
U.S. Pat. No. B5,605,571 discloses a combination of a hardening-accelerator with a high-range water-reducer for a hydraulic powder, containing a nitrate or sulfite component, a thiocyanic acid component, an alkanolamine component and a carboxylic acid component.
JP-A2002-226245 discloses a concrete mixture and a concrete composition, containing a trialkanolamine and a polycarboxylic acid or a salt thereof. JP-A01-246164 discloses an admixture for a hydraulic cement, containing an amidosulfonate and a water-soluble aminoalcohol. JP-A2002-080250 discloses a setting and hardening-accelerator containing a water-soluble aluminium salt containing a fluoride and an aluminium salt containing a sulfate, but not an alkali, alkaline metal, or chloride. JP-A2002-145651 discloses a cement composition containing C2S or C3S, and C3A and C4AF. WO-A2012/008517, published on Jan. 19, 2012, discloses a method for producing a hydraulic powder.